Cleaning and degreasing system



Juif 20 1942.v H. E. soMEs I CLEANING' AND DEGREASING SYSTEM 2Vshams-sheet 1 origina; Filed Feb; 8, 1935 Howard 522171495 umichATTORNEY Jan. 20, 1942. H. E. soMl-:s

.CLEANING AND DEGNEASING SYSTEM 2 Sheets-Sheet 2 Original' Filed Feb. 8,1935 .Howarc Ex/fl'cms/ BY 63. fm

ATTORNEY Patented Jan. 20,1942

cLEAmNG AND 2,270,642 e nEcaEAsiNG srsran -Howard E. Somes, GrossePointe Park, Mich., as. signor to Budd Induction Heating, lno.,Philadelphia, Pa., a corporation of Michigan original applicationFebruary s, 1935, serial No. 5,663, now raten: No. 2,180,126, datedNovember 12, 1939.

Divided and this application Febijuary 23, 1939, Serial No. 257,847

11 Claims. (Cl. 202-170) The present invention relates to a cleaning anddegreasing system, particularly adapted yfor the cleaning and degreasingof metallicvarticles. The most generally used cleaning and degreasingsolvents are organic compounds such as benzine, gasoline, oleum spirits,tetrachlorethylene, and the like. The vapors of most of the solvents incommercial use are heavier than air and the vapors of practically allvof these solvents vare contact With the solvent to be employed. Some.

of the most eiective solvents are organic solvents which .have toxicvapors. Other of the organic solvents are relatively volatile and willbe rapidly dissipated into the atmosphere, frequently causing lires andexplosions. Because of these characteristics, the methods heretoforeemployed have precluded, to a large extent, a

freedom ofchoice among these classes of solvents.

The process and system herein proposed utilizes, in one embodiment, asolvent in its liquid phase to remove the greatest bulk of theobjectionable dirt, ,grease and other adherent sub' stances. Inaddition, the system may utilize a spray, either alone cr with a liquid,for removing any dirt or grease remaining after the liquid treatment. Inorder to remove the last traces of dirt and grease remaining after thetreatment with the solventin the liquid phase, 1 utilize the solvents intheir vapor phases.

thereof. As` a result, the vapors condense to liquid upon contact -withthe surface of the' The work being cleaned has a temperaturepreferablybelow that of the vapors and below the condensation point work, and thisin eect permits only clean distilled solvent to come in contact with theWork during its final cleaning phase.

In systems heretofore used, the solvent when u sed in theliquicl phasehas performed more or less imperfectly since the bath quickly becomescontaminated with grease and dirt, and, since the solvent is muchheavier than the grease which it removes, the grease iioats to thesurface sor and adheres to the part being cleaned part is withdrawn. Y n,l

It is an important object of the present invention to provide a.continuous cleaning and de- Y greasing system in which solvents in theirhot liquid. cold liquid and in their vapor phases are when said employedsuccessively -to accomplish cleaning' and vdegreasing of work passingtherethrough.

It is a further object of the present invention to provide a cleaningand degreasingsystem having an enclosing shell sealed at its entranceend to preclude circulation of air or vapors of solvents therethrough.

Itis a further object of the'preseni; invention to provide a cleaningand degreasing system in which deiinite control over the system ismaintained at all times, both as to amounts of solvents used and as totime of contact of the metallic articles with such solvents.

It is an important object of the present invention to provide a cleaningand degreasing system wherein the work to be cleaned will passsuccessively through a hot agitated liquid solvent bath, a cold solventspray, and thence through a solvent vapor bath, under such conditionsthat these successive treatments eiect a thorough degreasing andcleaning of the work.

Further, it is an object to provide a cleaning and degreasing system inwhich the work, after the vapor bath, is raised to an elevatedtemperature substantially above the boiling point of the solvent,`thereby to vaporize and-drive od any Vadherent solvent imprisoned in themetal part,

after which such solvent is reclaimed.

It is a further object of the present invention to provide a cleaningand degreasing system in which a novel construction is employed `infahrlcation of that portion of the enclosing shell where electricallyoperated induction coils are. employed for heating purposes, whichconstruc- 'tion prevents the iiow of eddy currentsvfrom the inner to theouter shell. Other objects of this invention will appear in thefollowing description and vappended claims, reference being had to theaccompanying drawings forming a part of this specification wherein likereference characters designate corresponding parts in the several views.

Fig. 1 is a longitudinal section and side elevation or a portion of theapparatus utilized in a cleaning and degreasing system of the presentinvention.

Fig. 2 is a view similar to Fig. 1 showing a continuation of theapparatus shown in Fig. 1.

Fig. 3 is a'sectional view taken substantially in the bottom oftheV-shaped enclosures.

power driven endless chain I5 is operatively cononV the line 3-3 of Fig.1l in the direction ofthe arrows.

Fig. 4 is a view similar to Fig. 1 but-showings modified apparatus usedin a vapor phase system Flgf is a view similar to Fig. 2 but showing amodification thereof particularly adapted for use with the apparatusshown in Fig. 4.

Fig. 6 is a section taken substantially on theline 6 6 of Fig. 1 inthedirectionvof the arrowsshowing a preferred form of construction of theenclosing shell.-

Fig. 7 is a section taken substantially on the line 1-1 of Fig. 1in thedirection of thearrows.

Before explaining in detail the present invention it is to be understoodthat the invention is not limited in its application to the details ofconstruction and arrangement of parts illustrated in the accompanyingdrawings, since the v.invention is capable of other embodiments and ofbeing practiced or carried out in various ways.

' Also itis to be understood that the phraseology or terminologyemployed herein is for the purpose of description and not of limitation.and .it is riot-intended to limitthe invention claimed herein beyond therequirements of the prior art.

. A n apparatus particularly adapted for use with a cleaning anddegreasing system of the present invention .is shown in Fig. 1 andcomprises essentially @conveyor system of any conventional design. whichincludes a conveyor track II which maybe 'suspended from an enclosingshell-I2 and extendslongitudinally thereof. The track and carrier I3 asit follows the track I I.

y Asa part of my system I propose to locate, in` the enclosure or oven,suitable depressed porthe enclosure or oven structure in this manner isfacilitated. It is also possible, when the solvent r is-in liquid form,to have the surface thereof close to the top of the depressed portion,whereby to reduce the size of the air passage through the` oven.

` This provision of risers effects an up and down dipping motion of thework Il carried on the carrier I3 in the tank portions I6 and I'I.formed A v Ir cating grease from the conveyor system. This carrier byconduction and radiation.

construction also contemplates heating of the track II wherever this isnecessary, there being some heating of the track `from the chain and Theheating-means |03 is provided wherever necessary to maintain therequiredftemperature in the convveyor system.

The enclosing shell I2, as shown in Fig. 3, is a four sided enclosurewhich is open at each end to permit ready movementof the carrier I3 andwork I4 into, through and -out o'f the shell. At selected intervals theshell I2 is formed to provide the vat's or tanks I6 and I1 which areadapted to hold cleaning or solvent materials either in their liquid ortheir vapor phase. The materials used in fabrication of the shell I2depend upon the use to which the apparatus is to be put and thematerials to be used therein. In each instance the shell and thevats ortanks are formed of non-corrodible material s uch asv galvanized sheetmetal, concrete, glass-lined steel, porcelain, stainless steel, enameledsheet metal,

4tile or ythe like, the choice of material depending L shell aredepressed at selected intervals to provide a downward and upwardmovement of the Inec'ted withthe .carrier I3 and eifectsmovement of thecarrier I3 longitudinally of the" track II;

Where the cleaning system isof the continuous type as just described, itis desirableto maintain` the temperature of the chain II, and of thecarrier I3 on which the chain may be supported,

nabove that at which condensation of solvent vapors will occur.Accordingly I provide'means III,

' one form of which is shown in detail in Fig. '1, forheating the chainto such temperature. As

here shown by way of example, the heating means :comprise anelectrically actuated induction ff heating con. los which has e seidwhich is interby travel of the; chain Il and the carrier ."I3longitudinally of the enclosure. This causes a heating of the chain I5and the carrier I3. Other' types of heating means, such as resistanceheating or the like, may be employed for this upon the solvents to beused at each point along the length ofthe shell structure.

In the installation shown in Fig.- 1.1 propo to' utilize both the liquidand vapor phases of the cleaning and degreasing solvents. Accordingly Iprovide in a vat or tank .I0 a bath of liquid solvent, preferably anorganic compound Vchosen from the list previously mentioned, the

solvent being used either alone or in combination with'other liquidmaterials having a substantially higher boiling l point than thesolvent. The solvent used should preferably have vapors which areheavier than air.

- Heating means 20, such as steam coilsor the like, are placed in thebottom of the vat or tank I6 and are heated and controlled to maintainthe body of the liquid solvent at a temperature just below theboilingpoint thereof. In order to conserve the heat, the vat or tankv I6is preferably insulated or' formed of materials through which there is arelatively small amount-of heat translwhen using the solvent in itsiiquid phase-,in the vat or tank I6, itis advisable to maintain it atsuch a level that .the conveyor does not come in contact with theliquid. 'I'he, vapors which emanate from the liquid in the tank areheavier than air and 'the height of the risers is so chosen as toconfine a vapor column of sufv iicien't height to constitute a vbarrierto prevent substantial circulation of Aairlongitudinally through theenclosure I2. vThe necessary level of the liquid solvent is maintainedby feeding the liquid solvent at a constant rate through lthe solventfeed pipe 2I` and continually re- 'moving the excess through the`overilow 22. The .solvent nowing throughtheV overnow 22 is then vvpassedthrough' a water separator 23 and a still 24 to the clean solventstoragetank 25, from which -it is then pumped to the clean vsolvent supply line26...

In using solvent materials at temperatures .closely approximating theirboiling points, it is inevitable that some vaporization will occur.

.ing the surface of the liquid` relatively andere In order to preventloss of the solvent ma in the form of vapors I provide a series'ofcondenser coils 21 within the 'shell I2 andadjacent the four sidesthereof. The lconveyorcarrier and work pass through the interior of thecoils 21 before they pass into the liquid solvent in the vator tank I6.The condenser coils are cooled to a temperature suillciently below thetemperature of the vapors driven oi the liquid solvent to liquefy anyvapors which pass into this portion of the enclosure. The vapors uponcondensation to the liquid phase may drop back into the vat or tank I6,or may be divertedinto the overflow age thereof.

As the solvent in the vat or tank I6 is repipe 22, thus preventingwastquired to remove the first and consequently the greatest bulkl ofdirt or grease, it vis -advisable to provide a skimming paddle 2l whichconstantly agitates the surface of the liquid, and tends to prevent theformation of a surface scum containing the removed dirt and grease. Thisskimming paddle 28 tends to keep the surface scum in circulation sovthat it flows with'the Iliquid to the overflow pipe from whence it isremoved from the tank. This results in keepcleaner the recirculatingpump 3l and the conduit I l connected with the pipes 3l. AsA the work Ilpasses through this spray rinse. adhering dirt and grease particleswhich have been loosened by the heated solvent in the vat or tank Il areflushed of! thesurface of the work.

Where, after the spray rinse, it is found de'- sirable to provide astill further cleaning action, I proposeto subject the work to a bath ofsolvent vapors. and the cooling of the work upon passing through thecold spray `:serves the Purpose of lowering the temperature of the workto -a point where the solvent vapors o'f the subsequent bath willcollect thereon. By condensing distilled solvent vapors on the work. the

s cleaning action of the solvent may be obtained than would otherwise bethe case,

As'the work Il on the carrier I3 is moved longitudinally of theenclosing shell l2, it is Vdipped into the hot liquid solvent in the vator tank I6 and is then carried under and beneath the dependingvportionof the shell and conveyor which extend inwardly to a point adjacent thesurface of the liquid solvent. The work then is carried upward along thefriser and away from the vat or tank I6 and therewithout, however,running any danger of additionally contaminating the surface of the workby dirt or grease carried by the solvent. as might perhaps occur in thecold spray or in the/ liquid tank.

When the` vapor bath is to be used, the work passes from the spray rinseSli'to a vat orvtank I1, being carried downwardly thereto through apassage the length of which -is sumcient to containi'a heavy enough bodyof solvent vapor so that displacement thereof by any atmospheric airentering the ends of the oven is minimized.

Here, as in the case of the vat or tank I0, .I may employ insulatingmaterials'either in the 1-'formation of the vat or tank I'l, or I maysurround the vat'or tank I'I with heat insulating Vmaterials which areeffective to prevent subafter passes through the spray rinse 30 which.V

in this instance consists of a series (if-'connected pipes 3l havingsmall perforations therein from which cold solvent under pressure is'sprayed as sharp needle-like sprays directly upon the surface of thework I l. In the embodiment here shown and as shown in more detail inFig. 3, the connected pipes 3l extend around thesides and bottom of theshell I2 as well as longitudinally thereof for any desired distance.Liq-- uid solvent is supplied in predetermined amounts through thevconduit 32 which communicates through a feed pipe 33 with the fillingline 2l. A valve 3l permits control of the amount of solvent drawn fromthe conduit 23. In order to prevent contactsof the liquid solvent with4the conveyor system, and consequent grease removal therefrom', baiiles Iarevsecured to the shell I2 and extend downwardly therefrom anadconstantial heat losses therethrough. 'I'here is this difference,however; here' the purpose is to utilize the solvent inV its vaporphase, so the walls of the enclosure I2` are also insulated against heatloss so that when they become heatedlby contact with the heated vaporsof the solvent.

they will retain sufllclent of the heat to preclude chilling of thevapors and consequent conc Il and M and suitable electric switches orconverge inwardly at their ends to form an enclosure which shields theconveyor from direct contact with theliquid solvent of the spray rinse.

Directly' beneath the spray rinse u r provide a catch basin 35 in whichcooling coils 20 are placed. The catch basin `35 receives solvent fromthe'feed conduit 32 and from the spray rinse 30. As the work Il retainssome heat'byl reason of its passage through the heated solvent in thevat or tank It,- the solvent sprayed thereon becomes heated so that`subsequent cooling is required. -Unless cooled, the solventpassing fromthe spray rinse would vaporize in` stantly upon contact with the heatedworkl and would not effect the agitation, scrubbing' and flushing actiondesired. As the liquidsolv'ent accumulates in the catch basin 35 it iscooled and withdrawn from the bottom thereof through the conduit 3l andthereafter through trois (not shownv but indicated, diagrammatically atl5). By the use of thehigh and low level thermocouples vthe level of thevapors in` the discharge end of the vat or tank I5 is definitelycontrolled within predetermined fixed limits; for example. this electriccontrol system is'l' so arrangedthat ,if the highlevel thermocou- -pleI2 is heated by the vapor, the Vilow of current to the heating device l2is decreased and the solvent is boiled less vigorously. l When, how vever, the vapor drops below the low level thervmocouple M, indicatingadecrease in temperature, the nov! of .current to-theheating device I2is' increased `and the .temperature of the solvent is increased. Thisresults in the formation of an increased amount of hot vapors and thesubsequent mixture of thevapors at a predetermined level, depending uponthe placement of the thermocouples 42 and 44.

Tov prevent flow of 'vapor longitudinally of` the tunnel, I provide aseries of condenser coils 4B between the work ent end of the spray rinsethevat l1.

ii fcollsamg-similar in construction.v and operatlon'to thecondensercoils 21, whenltheheaty ed' vapors contact .withthecooled zonewIthin'the' condensercilslthe vapors vvare liquefied and when so liqueiied maydropv back into the tank l Jfromwhichv they issued; I have found thatthe use of the solvent inits vapor phase in the tank treatingclmmbervil, afterwhich the workmay then` pass nto -fother'f treating:chambers '.(notl shownli such :as ovensor the like.

Various ftypesof .construction-may. employed vin the constructionfoitheenclosure il. Where .or vat i1`issuperiorto its use in aliquid-.bath

or spray because the vapors are pure @distilled 4 solventand are freeffrom impurities which are aptto be present in a Abody of the solvent asaliquid. -By -using the vapors only. the grease,.dirt

and the like `remain in the liquid solventfandso dov not contaminate thecleaned surface. 1

vAfter passingthrough the solventvapors in the vat or tank I1, the workI4 isfcarriednpwardly-through induction heating coils 50' where it isheated to a suilicient temperature to vaporize vany adhering solventparticles andv to dry the surface thereof. 'I'he use of inductionheating coils at this point is preferable to other forms of heatingsystemssince the heat so applied raises the temperature of the metalparts only above the top of the 'surrounding vapors or air. 'I'he usekof induction heating coils minimizes lthe 'danger of explosionsoccurring in the tunnel as by this means the number of heated partsinside the tunnel and in'contact with the vapors is reduced. Theuse ofvradiant or conductive heating means requires placement of the heatingmeans inside the tunnel and in contact with the vapors therein. Suchheating means depends upon a circulation of air or heated vapors tocarry the heat from the heating means to the object to be heated. ThereIis an unavoidable heat loss in/this transfer which must bevprovided forby maintaining .the heating means at temperatures substantiallyhigherthan required temperatures for heating the article undergoing treat-lAfter passing through the induction heating coils 50, the work passesinto a drying over 5| (Fig. 2) which is heated in any desired manner andto any desired temperature. I'he shell I2 at the points adjacent theinduction heating coils il and surrounding the oven portion 5i isinsulatedto cut down the heat loss therethrough.

y there is;Y as shown in Fig. 6. an inner shell-Bland 10 i te'rials.v`.I n aspreferred construction these shells an'outer shell 6|.hbolhrforxned of magnetic maarespaced apart and thermal insulatlngmariall2 is interposed therebetween. induction heating means, it has beenfound that the usual types of'metallic connecting members .employed toholdthe inner shell Il in place act as conductors of eddy currentspassing into the `inner shell Il, these eddy ,currents` flowingthroughvthe connections tothe outer 4shell which becomes heatedthereby.. This results in a considerable power loss which cuts-down theeiilciency of the oven. The-use of the thermal insulating material 62between the two shellsis of no assistance in reducingthis loss. I havetherefore provided a ymodified form of connecting member vfor use inovens heated by induction heating v means, which, when used to connectthe` inner shell Il and the outer shell Il, prevents the ilow ofeddyvcurrents fromthe shellv SI to the shell 6l. As here shown, theconnector comprises end members 63 and 64 connected'to flanges II and 66secured respectively to the outer and inner shellsl and ill. The membersil and may bel formed of any desired material and are connected by acenter member 81 formed of any p referred dielectric material, such asporcelain,`mica or the like. The use of the dielectric center member 61between lthe adjoining ends .o'f the members 63 andllrhas been found toeliminate the iiow of eddy currents from the inner shell il to the outershell 6I and cuts down the loss herewith the solvent maintained in itsvapor phase at all stages except the spray rinse stage. Figs. 4 and 5represent, therefore, a modiiled form of apparatus adapted particularlyfor use -in a cleaning and degreasing system wherein the sol- In thismanner heat is-.conserved within the enclosure I2 at these points. Asshown, the oven is constructed with a sloping bottom portion inclineddownwardly toward the vat or tank I1. This directs any liquid solventparticles vor the heavy vapors of the solvent downwardly toward the vator tank` I1 and so conserves solvent materials which otherwise wculdbewasted in carrying out the process.

As the work passes from the oven 5l it travels through a passageway ofmore restricted crosssectional area to a tack ragging and inspectionstation B2. 'As the work cools progressively after leaving the heatingsection MLthe reduction of the cross-sectional area of the passagewaytends to minimize the amount of air which otherwise would be introducedinto theoven 5I. The work then passes from the inspection station l2toga vent is employed in its vapor phase in both of the treating vats ortanks 10 and 1|. In such modiflcation. the tank I0 is similar inconstruction and operation'to the tank I1 heretofore described andprovides columns of the heavy vapors which prevent any substantialcirculation of air through the enclosure. In this construction I employa solvent boiling -heater 'I2 of the electrically actuated immersiontype. The heater 12 is controlled by high and lowlevel thermocouples 13and 14 acting through electrically operated control members showndiagrammatically-at ll.

It is an important feature oi' my inventicnthaty in the presentembodiment the temperature of -the articles treated may be so controlledthat the same lsalwa'ys below the temperature of superheated solventvaporand consequently no evaporation ofthe liquid solvent4 in the spraymay occur. `Such control is achieved by the thermocoupl'es 13 and 14,either by controlling'the temperature of the vapor, or by controllingthe level of vapor in the bath. Por the last 'type of control, in order`toprevent overheating of the work or articles treated, the thermocouple13 is set for a lower level, and with the same` rate of conveyor travelthe lower level in the vapor bath downward opening.

aarden Flow of the vapor Vfrom the vat or tank is prevented by condensercoils ltsimilar' in construction and operation to the condenser coils 46(Fig. 1) heretofore described in detail. Here, as -in the case of thevat or tank I1, the tank is heat insulated or is formed of heatinsulating materials. Work Il on the conveyor is carried into andthrough the solvent vapors in the tank and then passes through the sprayrinse 30 heretofore described in detail. Thereafter the work passes intothe vat or tank Il in which there is supplied a'quantity of superheatedsolvent vapors. The vat or tank Il is of similar construction andoperation as the vats or tanks heretofore described and is soYconstructed that the vapors provide a column which prevents subistantial circulation of air 4currents through the work, condenser coils84 similar in construction and operation to the coils 46 are interposedbetween-the exit end of the spray rinse 30 and the entrance end of thetank ll. After passing through the induction heating coils 83, the workM passes through an oven 5I, tack ragging and inspection zone 52 andinto a spray booth, dip tank,or other surface treating member 53, as hasbeenpreviously described.

the work leaves the last vapor phase treatment, there is a condensate ofdistilled solvent which adheres to the surface or is imprisoned in thepores of the metal. The cleaning and degreasing system of the presentinvention provides a method and means for reclaiming such solvent.

The work is heated to an elevated temperature as it travels through theinductionheating coils tank'. As shown in Figs. 2 and 5, the enclosureis formed as a hood which is provided with a and in the hood -is heatedin the oven and by contact with the heated work, and rises against thetop of the enclosure and the hood. This combination eiects a seal which.prevents any substantial drawing of air inwardly into the tunnel fromthe discharge end thereof. There-is,1

into further contact with the work.

Thus, considered from. one of its broader aspects, my inventioncontemplates providing a no'vel degreasing and .cleaning structure of a75 .59 portion thereof; electrically actuated and coning substantiallyequal in each of s aidl stages and` being at such a point to producebest dissolving continuous and multiple stage type, in which thesurfaces of the articles treated are subjected in each of the severalstages of treatment to the action of hot liquid solvent, said hotliquid` sol'- vent being applied rst in the form of a hot liquid bath ofsolvent, and thereupon produced by contact of the cold liquid with thehot surface of the articles, and the hot vapor with the cold surface ofthe articles, the resulting temperature of the solvent at the surfacesof the articles beaction upon oil and impurities; and in which systemthe hot solvent produced at the surface of the articles treatedincreases in its `purity in eachof the' succeeding stages of treatment.

This application Vis adivision of application Serial Number 5.663,'1edFeb. 8, 1935, now Patarticles and comprising a conveyor, a tunnel-like Aenclosure surrounding said conveyor, the bottom The air in the enclosurethe vapors and carrying the vapors forwardly of said enclosure beingformed to provide vats or tanks atspaced intervals in the lengththereof,

said vats or tanks being adapted to contain fluid materials capable ofeffecting a cleaning or degreasing of the surface of the-metallicarticle to be cleaned or degreased, means to prevent substantialcirculation of air currents inthe direction of the length of theenclosure and comprising a series of enclosed risers communicating withsaid vats or tanks, a cold solvent spray in each of the risers locatedbetween two adjacent tanks above the upper level of said tanks,electrically actuated and controlled heating elements in said vats ortanks adapted to maintain the uid materials therein atpredeterminedtemper atures higher Vthan atmospheric temperatures, and high and lowlevel thermocouples electrically connected with said heating means andadapted to control the vapor level within said 4vats or tanks bycontrolling the heating thereof. 2.*An apparatus for' cleaning anddegreasing metallic articles and comprising a conveyor extending throughan enclosing shellsaid shell being thermally insulated at selectedintervals and formed to provide vats or tanks in the bottom vapors ataheight suiilcient to prevent substantial circulation of airthrough.said tanks; the risers located between two adjacent tanks beingprovided withl cold solvent spraying means situated above the upperlevel of said columnsl of 3. An apparatus for cleaning and degreasingmetallic articles and comprising a conveyor, an enclosing shellextending around the four sides thereof, a series of tanks formed insaid shell at -selected intervalsrelectrically controlled heating 1elements placed within said tanks and adapted tomaintain a body of a,fluid in the tanks at a predetermined temperature, induction heatingcoils within said shell and arranged to surround a metallic articlecarried on said conveyor whereby the article is heated by induction totemperatures sucient to vaporize adhering solvent and dry the surfacethereof without materially raislng the temperature of the enclosingshell or the surrounding atmosphere l A, bottom in said sneu @diecastthe ingiuctionlh ing` coils and leading to lan adiacent..; tank,

a hood extending overthevdigcharge 4opening adaptedto entrap heated `airto preventoutward" ilow of the vapors, said inclined bottomflbeinarranged in such a manner that'theheavy va-.1'

` pors now downwardly' in contact therewith are returned to the adjacenttank. l v

4. An apparatus for cleaning and degreasing systems in which an objectto be cleaned is car-"- ried on a conveyor system through successivezones for treatment with solvents in th'e vapor l phase and in theliquid phase; saidapparatusin` cluding a conveyor system, heating meansassociated therewith and adapted to heat the con.

the first, a spraying device above the liquid level" in said secondtankl for spraying an article car-ig ried by the conveyor above thesecond tank, a

5.1m apparatus for cleaning and degreasing Y systems in which an objectto be cleaned is carried on a conveyor system through' successivezonesfor treatment, with solvents in the vapor l phase and in the liquidphase; said apparatus including 'a conveyor system, heating meansassociated therewith and adapted to heat the con-v veyor system totemperatures above the temperature of condensation of the solvent vaporswherever the conveyor system comes in contact therewith, and enclosing.bai'iles associated with' said conveyor in the zones wherein-thesolvent is employed in its liquid phase.

6. An apparatus for cleaning and degreasing systems in which an objectto be cleaned is carried onv a conveyor system through successive zonesfor treatment with solvents in the vapor phase and in the liquid phase;said apparatus inf cluding a conveyor system, induction heating coilssurrounding only said conveyor system and adapted to heat selected partsthereof to Itemperatures above the temperature of condensation of thesolvent vapors wherever the conveyor system comes in contact therewith'.

7. An apparatus for cleaningand degreasing systems in which an object tobe cleaned is car- 'ried on a conveyor system through'successive zonesfor treatment with solvents in the vapor phase and in the liquid phase;said apparatus including a conveyor system, induction heating coilssurrounding said conveyor -system and adapted to heat ,selected partsthereof to temperatures above the temperature of condensation of thesolvent vapors wherever the'conveyor system comes in contact therewith,and enclosing bafiles associated with said conveyor in the zones whereinthe solvent is employed in its liquid phase. I

8. In an apparatus of the continuous multiple v stage treatment type forcleaning and degreasing, a conveyor, means for heating said conveyorabove the temperature of condensation of vapor of the solvent employedin the apparatus, an en' closing 'shell extending around the four sidesof said conveyor, a series of tanks formed in said shell at selectedintervals, said' tanks adapted to maintain a bodyof solvent at apredetermined '.temperature, and any induction heating coil within saidshell and adapted to surround a metallic article carried on saidconveyor so as to heat.

the article by induction to a temperature suiliotfni nen or the sur-jraising-'the "temperature vrounding atmosphere of vaporsaid tanksv.being adapted :for treatment of an'fobiecton thecon' vcyor -with hotliquid, with m01 liquid and with s1Yent.-1n"the vapor phase.

three adjacent tanks across which the conveyor extends, the first tankcontaining a liquid 'sol-- vent constituting a nrst; bath foran article,a -heater within said tank for" heating the liquid solvent therein, thesecond tank being adjacent pump for circulating solvent from the secondtank to said spraying device, a cooling device within said second tankfor the solvent to be sprayed, the third tank having therein a heaterfor boiling the solvent to provide `vapor phase contact with an articlewhereby :clean solvent is provided, said conveyor being constructed tocarry an article within the casing -into the rst and third tanks butonly above thesecond tank.

I10. An apparatus particularly adapted for cleaning and degreasing thesurfaces of metallic articles and comprising a conveyor, a tunnellikeenclosure surrounding said conveyor, the bottom of. said enclosure beingformed to pro.- vide vats or tanks at spaced intervals in the lengththereof, said vats or tanks being adapted to contain vfluid materialscapable of effecting a cleaning or degreasing of the surface of themetallicarticle to be cleaned or degreased, means to prevent substantialcirculation of air currents in the direction of the length of theenclosure and comprising a series of enclosed risers communicating withsaid vats or tanks, a cold solvent spray ln each of the risers locatedbetween two adjacent tanks above the upper level'of said tanks,electrically actuated and controlled heating elements in said vats ortanks adapted to maintain thefluid materials therein at predeterminedtemperatures higher than atmospheric temperatures, and means connectedwith said heating means and responsive to the vapor level within saidvats or tanks for controlling the h'eating thereof.

11. In an apparatus of the continuous multiple-stage type for cleaningand degreasing, an

article conveyor, a plurality of separate baths' ticles independent ofthe temperature of the .euri-- rounding vapor during their travelthrough said-- passageway to raise the temperature of the articleshigher than the surrounding vapor in the passageway, whereby liquidsolvent on the article is evaporated and the surrounding atmosphere ofvapor is not materially lightened by increase of temperature.

HOWARD n. soms.

